XRSession: updateRenderState() method

Syntax

updateRenderState()
updateRenderState(state)

Parameters

state Optional

An optional object to configure the XRRenderState. If none is provided, a default configuration will be used.

• baseLayer Optional: An XRWebGLLayer object from which the WebXR compositor will obtain imagery. This is null by default. To specify other (or multiple) layers, see the layers option.
• depthFar Optional: A floating-point value specifying the distance in meters from the viewer to the far clip plane, which is a plane parallel to the display surface beyond which no further rendering will occur. All rendering will take place between the distances specified by depthNear and depthFar. This is 1000 meters (1 kilometer) by default.
• depthNear Optional: A floating-point value indicating the distance in meters from the viewer to a plane parallel to the display surface to be the near clip plane. No part of the scene on the viewer's side of this plane will be rendered. This is 0.1 meters (10 centimeters) by default.
• inlineVerticalFieldOfView Optional: A floating-point value indicating the default field of view, in radians, to be used when computing the projection matrix for an inline XRSession. The projection matrix calculation also takes into account the output canvas's aspect ratio. This property must not be specified for immersive sessions, so the value is null by default for immersive sessions. The default value is otherwise π * 0.5 (half of the value of pi).
• layers Optional: An ordered array of XRLayer objects specifying the layers that should be presented to the XR device. Setting layers will override the baseLayer if one is present, with baseLayer reporting null. The order of the layers given is "back-to-front". For alpha blending of layers, see the XRCompositionLayer.blendTextureSourceAlpha property.

Return value

None (undefined).

Exceptions

InvalidStateError DOMException

Thrown in any of the following situations:

• The XRSession has already ended, so you cannot change its render state.
• The baseLayer was created by an XRSession other than the one on which updateRenderState() was called.
• The inlineVerticalFieldOfView option was set, but the session is immersive, and therefore, does not allow this property to be used.

NotSupportedError DOMException

Thrown in any of the following situations:

• The layers option is used in a session that has been created without the layers feature.
• Both the baseLayer and layers options are specified.

TypeError

Thrown if the layers option contains duplicate instances.

Examples

Adding a baseLayer

This example creates a WebGL context that is compatible with an immersive XR device and then uses it to create an XRWebGLLayer. The method updateRenderState() is then called to associate the new XRWebGLLayer.

function onXRSessionStarted(xrSession) {
  let glCanvas = document.createElement("canvas");
  let gl = glCanvas.getContext("webgl", { xrCompatible: true });

  loadWebGLResources();

  xrSession.updateRenderState({
    baseLayer: new XRWebGLLayer(xrSession, gl),
  });
}

Setting the layers array

To use WebXR layers, the XR session needs to be created with the layers feature descriptor (see XRSystem.requestSession()). You can then create various WebXR layers such as

• XREquirectLayer
• XRCubeLayer
• XRCylinderLayer
• XRQuadLayer

Other layers, such as XRProjectionLayer or XRWebGLLayer are also available.

Layers will be presented in the order they are given in the layers array, with layers being given in "back-to-front" order.

const xrSession = navigator.xr.requestSession("immersive-ar", {
  optionalFeatures: ["layers"],
});

function onXRSessionStarted(xrSession) {
  const glCanvas = document.createElement("canvas");
  const gl = glCanvas.getContext("webgl", { xrCompatible: true });
  const xrGlBinding = new XRWebGLBinding(xrSession, gl);
  const projectionLayer = new XRWebGLLayer(xrSession, gl);
  const quadLayer = xrGlBinding.createQuadLayer({
    pixelWidth: 1024,
    pixelHeight: 1024,
  });

  xrSession.updateRenderState({
    layers: [projectionLayer, quadLayer],
  });
}

Specifications

Browser compatibility

See also

• WebXR Device API
• XRRenderState
• XRSession.renderState